JP4316283B2 - Tensile anchorage structure and tendon stress measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tension member fixing portion structure that can be used for a fixing portion in a tension material such as a ground anchor or a PC (prestressed concrete) structure, and a stress measurement method for the tension material.
[0002]
[Prior art]
For tension materials such as ground anchors, PC structures, suspension bridges and cable-stayed bridges, there are problems such as breaking when excessive tension is applied or loosening due to changes over time. It is necessary to quantitatively measure whether the tension is acting in order to evaluate the safety of the structure.
[0003]
[Patent Document 1]
A magnetostrictive method as disclosed in Japanese Patent Application Laid-Open No. 2002-173935 is used as a stress measuring method for a tendon. The stress measurement method by the magnetostriction method is that when a load is applied to a ferromagnetic material, anisotropy occurs in the permeability, the permeability in the load direction increases, and conversely, the permeability in the direction perpendicular to the load direction decreases. This is a technique for measuring the direction and magnitude of the principal stress by detecting the difference between the two magnetic permeability using a magnetostrictive sensor.
[0004]
The stress measuring method for tendon described in Japanese Patent Laid-Open No. 2002-173935 uses a magnetostrictive sensor for an anchor nut fixed to the tendon or an interposed member interposed between the anchor nut and the anchor plate. The difference between the stresses obtained at each measurement point is obtained, and the stress (tension) applied to the tendon is evaluated based on the difference.
[0005]
For this evaluation, for example, stress (tension) is applied to a test piece made of the same material as the tendon, and the correspondence between the stress value applied to the test piece and the output value from the magnetostrictive sensor is obtained in advance. Next, in the actual stress measurement of the tendon material, the magnetostrictive sensor is applied to the tendon material, and the actual stress is estimated from the output value of the magnetostrictive sensor from the above correspondence.
[0006]
[Problems to be solved by the invention]
However, the above-mentioned correspondence relationship is not always the same between an actual tendon and a test piece, and there is a problem that it is not accurate to estimate the stress from the output value of the tendon magnetostrictive sensor.
[0007]
The present invention has been developed to solve such problems. That is, it is possible to provide sufficiently accurate measurement only by stress measurement by the magnetostriction method, and to provide a tension member fixing portion structure and a tension material stress measurement method capable of easily measuring the aging transition of stress. .
[0008]
[Means for Solving the Problems]
The tension member fixing portion structure of the present invention includes a tension member (1), a fixing member (4) that is fixed to the distal end portion of the tension member (1), and applies tension to the tension member (1) by tightening. An anchor plate (3) disposed at a position closer to the opposite side of the tip of the tension member (1) than the fixing member (4) and receiving the fixing force of the fixing member (4) ( 1) The fixing portion structure of 1), wherein the member to be measured (5) having an annular shape is interposed between the anchor plate (3) and the fixing member (4) and covered with the seal piece (8). The outer surface of the member (5) is a measurement surface by a magnetostriction method (hereinafter referred to as “magnetostriction method measurement surface”) (5A) and a measurement surface by a strain gauge method (hereinafter referred to as “strain gauge method measurement surface”) ( 5B), and a strain gauge is attached to the strain gauge method measurement surface (5B).
[0009]
According to the present invention, sufficiently accurate measurement can be performed only by the stress measurement by the magnetostriction method, so that the transition of stress over time can be easily measured. If the strain gauge is operating soundly, continuous monitoring is performed using the strain gauge method, and only when an abnormality is detected, the stress is measured using the magnetostriction method, and whether there is an abnormality in the strain gauge. Alternatively, it can be determined whether the member to be measured (5) is abnormal. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
In addition, when the outer side of the member to be measured (5) is covered with the seal piece (8), the member to be measured (5) can be protected, and the member to be measured (5) can be stably measured.
[0010]
If the cross-sectional shape of the member to be measured (5) is a polygon, a plurality of measurement surfaces (5A, 5B) can be formed, and it can be expected that the stress of the tendon (1) can be measured with higher accuracy.
[0011]
If the cross-sectional shape of the member to be measured (5) is an even-numbered polygon, the magnetostrictive method measurement surface (5A) and the strain gauge method measurement surface (5B) can be plural and the same number, and the tension material (1 ) Can be expected to perform the stress measurement with higher accuracy.
[0012]
When the magnetostrictive measurement surface (5A) and the strain gauge method measurement surface (5B) are alternately provided in the circumferential direction of the member to be measured (5), a measurement result with little bias can be obtained, and the tension material (1) It can be expected that the stress measurement is performed with higher accuracy.
[0013]
When a plain washer (6) is interposed between the fixing member (4) and the member to be measured (5), the stress distribution in the cross-sectional direction on the member to be measured (5) can be made uniform, and the measurement accuracy Can be increased.
[0015]
If the tip of the fixing member (4) and the tension member (1) are covered with the anchor cap (10), the tip of the fixing member (4) and the tension member (1) can be protected, and the member to be measured (5 ) Can be measured stably.
[0016]
If the seal piece (8) and the anchor cap (10) are integrally formed, the number of parts can be reduced and the manufacturing cost can be reduced. It can be done easily.
[0017]
When the seal piece (8) and / or the anchor cap (10) is filled with grease (9), the fixing member (4) and the tip of the tension member (1) and / or the member to be measured (5) are protected. It is possible to perform stable measurement of the member to be measured (5).
[0018]
The stress measuring method for a tendon according to the present invention includes a tendon (1), a fixing member (4) that is fixed to the tip of the tendon (1), and applies tension to the tendon (1) by tightening. An anchor plate (3) disposed at a position closer to the opposite side of the tip of the tension member (1) than the fixing member (4) and receiving the fixing force of the fixing member (4) ( 1) A stress measuring method of a tension member (1) having a fixing portion structure of 1), wherein a member to be measured (5) having an annular shape is interposed between an anchor plate (3) and a fixing member (4). The outer surface of the member to be measured (5) is a magnetostriction method measurement surface (5A) and a strain gauge method measurement surface (5B), and a strain gauge is attached to the measurement surface (5B) by the strain gauge and magnetostriction method measurement is performed. The detection probe of the magnetostriction measuring device is applied to the surface (5A), and it is tightened when the tension material (1) is installed. Applying a load, collecting the stress value of the strain gauge by the strain gauge method and the output value of the magnetostriction measuring instrument, obtaining the stress sensitivity of the magnetostrictive measuring instrument, and measuring the stress after installing the tendon (1), It is characterized by being performed by a magnetostriction method.
[0019]
According to the present invention, sufficiently accurate measurement can be performed only by the stress measurement by the magnetostriction method, so that the transition of stress over time can be easily measured. If the strain gauge is operating soundly, continuous monitoring is performed using the strain gauge method, and only when an abnormality is detected, the stress is measured using the magnetostriction method, and whether there is an abnormality in the strain gauge. Alternatively, it can be determined whether the member to be measured (5) is abnormal. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
[0020]
In addition, when the strain gauge is operating soundly, continuous monitoring is performed by the strain gauge method, and only when an abnormality is detected, the site can be visited and stress measurement can be performed by the magnetostriction method. Whether the gauge is abnormal or the member to be measured (5) is abnormal can be determined. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
[0021]
Further, since the stress sensitivity of the magnetostriction measuring device is obtained when a tension load (preload) is applied at the time of installation of the tension material (1), the same quality as the tension material (1) is obtained in advance by, for example, a laboratory. It is not necessary to collect stress sensitivity using a material, and the measurement work can be simplified. That is, stress sensitivity can be collected by a tension load (preload) that is essential when the tension material (1) is installed, and an extra step (collecting stress sensitivity in a laboratory) can be omitted.
[0022]
When the cross-sectional shape of the member to be measured (5) is polygonal, and the stress measurement by the magnetostrictive method and the stress measurement by the strain gauge method are performed at a plurality of locations, the magnetostrictive measurement surface (5A) and the strain gauge method measurement A plurality of the surfaces (5B) and the same number can be provided, and it can be expected that the stress of the tendon (1) can be measured with higher accuracy.
[0023]
When the cross-sectional shape of the member to be measured (5) is an even-numbered polygon and the stress measurement by the magnetostrictive method and the stress measurement by the strain gauge method are performed at the same number of places, the magnetostrictive measurement surface (5A) and the strain are measured. A plurality of gauge method measurement surfaces (5B) and the same number can be used, and it can be expected that the stress of the tendon (1) can be measured with higher accuracy.
[0024]
The magnetostrictive method measurement surface (5A) and the strain gauge method measurement surface (5B) are alternately provided in the circumferential direction of the member to be measured (5) so as to perform stress measurement by the magnetostriction method and stress measurement by the strain gauge method, respectively. Then, a measurement result with little deviation can be obtained, and it can be expected that the stress of the tendon (1) can be measured with higher accuracy.
[0025]
By averaging the stress measurement values obtained by the magnetostriction method and the strain gauge method measured at a plurality of locations, a measurement result with less bias can be obtained, and the stress measurement of the tension material (1) can be performed with higher accuracy. Can be expected.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In this embodiment, the present invention is applied to a PC anchor.
[0027]
FIGS. 1 to 5 relate to the first embodiment, and FIG. 1 is a longitudinal sectional view of a PC anchor and each part thereof. The PC anchor embeds a portion (hereinafter referred to as “embedded portion”) 1B other than the tip portion 1A of the PC steel rod 1 (corresponding to the “tensile material” in the claims) in the concrete 2 to provide the concrete 2 The nut 4 is fastened to the part 1A protruding from the surface of the steel (hereinafter referred to as “bolt part”) via the anchor plate 3, thereby introducing tension into the PC steel bar 1 and generating stress inside the concrete 2. It is what Specifically, a portion 1B of the PC steel bar 1 excluding its tip 1A is embedded in the concrete 2, and is fixed to the concrete 2 with cement milk or the like in the concrete 2.
[0028]
A bolt 1A is formed by forming a thread at the tip of the PC steel rod 1, and the bolt 1A is disposed so as to protrude from the surface of the concrete 2.
[0029]
An anchor plate 3 is externally fitted on the bolt portion 1A of the PC steel bar 1 protruding from the surface of the concrete 2, and then a member to be measured 5 is externally fitted, and a plain washer 6 is externally fitted. Then, the nut 4 is screwed into the bolt part 1A of the PC steel rod 1 from the plain washer 6 side, the anchor steel rod 1 is fixed to the concrete 2, and the tightening force of the nut 4 is further increased, whereby the PC steel rod 1 Tension is introduced into this, which adds stress to the concrete 2.
[0030]
Of course, the tension (tension) applied to the PC steel bar 1 and the stress (compressive force) applied to the member to be measured 5 have the same “action, reaction” relationship and are therefore the same. Measuring the stress of 5 is synonymous with measuring the tension (tension) of the PC steel rod 1.
[0031]
FIG. 2 is a plan view of the member 5 to be measured viewed from the axial direction, and FIG. 3 is a longitudinal sectional view of the member 5 to be measured. The member to be measured 5 has a cylindrical shape, the longitudinal cross-sectional shape of which is a hexagon, and a central hole through which the PC steel rod 1 passes is formed at the center. The six outer surfaces of the member 5 to be measured are alternately magnetostrictive measuring surface 5A and strain gauge measuring surface 5B in the circumferential direction, and strain gauges are attached to the strain gauge measuring surface 5B. In FIG. 2, the outline of the member to be measured 5 represented by a bold line is the strain gauge method measurement surface 5B, and a strain gauge is attached.
[0032]
The cross-sectional shape of the member to be measured 5 is formed substantially the same as the cross-sectional shape of the nut 4. This is because an axial stress is applied to the member to be measured 5 by tightening the nut 4 as will be described later, but a substantially uniform stress is applied in the cross-sectional direction. Further, the member to be measured 5 preferably has a small initial residual stress. For example, it is desirable that the member to be measured 5 is formed in this shape and then subjected to heat treatment or by machining.
[0033]
The flat washer 6 is formed so that its cross-sectional shape is substantially the same as or larger than the cross-sectional shape of the member 5 to be measured. This is also for making the stress in the cross-sectional direction of the member 5 to be measured uniform when the nut 4 is tightened.
[0034]
As described above, the nut 4 is screwed into the bolt portion 1A of the PC steel rod 1 with the plain washer 6, the member 5 to be measured, and the anchor plate 3 interposed therebetween. A compressive force is applied to 5 and the anchor plate 3, and a tensile force (tension) is introduced to the PC steel rod 1, and stress (compressive force) is applied to the concrete 2.
A cap nut 7 is screwed into the bolt portion 1A on the tip end side of the PC steel rod 1 with respect to the nut 4, and the cap nut 7 is fastened to the bolt portion 1A so as to be in contact with the nut 4. Is located. The cap nut 7 is for supporting an anchor cap described later.
[0035]
The member to be measured 5 and the flat washer 6 are covered with a cylindrical seal piece 8, and the seal piece 8 is filled with grease 9. Thereby, while being able to protect the to-be-measured member 5, it can control from corrosion.
[0036]
The nut 4 and the tip of the PC steel rod 1 protruding from the nut 4 are covered with an anchor cap 10 whose tip is closed, and the opening edge of the anchor cap 10 is the end of the seal piece 8 on the tip side. It comes in contact with the edge.
A diameter-reduced portion 10A having a diameter smaller than that of the other portion is formed at a position closer to the distal end side than the opening end of the anchor cap 10, and the diameter-reduced portion 10A is fitted to the peripheral surface of the cap nut 7 almost exactly. It is supposed to be. Thereby, the anchor cap 10 covers the front-end | tip part of the PC steel bar 1, and the nut 4, and protects these.
[0037]
FIG. 4 is an enlarged longitudinal sectional view of the seal piece 8. O-rings 11 are positioned at both end edges in the axial direction of the seal piece 8, and the one on the front end side is interposed between the anchor cap 10 and the one on the rear end side is interposed between the seal piece 8. . This prevents the grease 9 filled in the seal piece 8 from leaking.
[0038]
Next, the measurement of the stress of the member to be measured 5 will be described.
In measuring the stress of the member 5 to be measured, a tension load is applied by a jack when the PC anchor is installed. At this time, a detection probe of a magnetostriction measuring device is applied to the magnetostrictive measurement surface 5A of the member 5 to be measured, and the output value is detected, and the measurement is performed by the strain gauge attached to the strain gauge measurement surface 5B of the member 5 to be measured. The stress value applied to the member 5 is measured. Thereby, the correspondence with the output value by the magnetostriction method, that is, the stress sensitivity of the magnetostriction measuring device is obtained. FIG. 5 is a graph showing the relationship between the stress value and the output value of the magnetostriction measuring instrument, that is, the stress sensitivity of the magnetostriction measuring instrument.
[0039]
As described above, since the stress sensitivity of the magnetostriction measuring device is obtained when a tension load (preload) is applied when the tension material is installed, the same material as the tension material is used in advance by, for example, a laboratory. It is not necessary to collect stress sensitivity, and the measurement work can be simplified. That is, the stress sensitivity can be collected by a tension load (preload) that is essential when the tendon is installed, and an extra step (collecting stress sensitivity in the laboratory) can be omitted.
[0040]
And the measurement of the stress of the member 5 to be measured after the PC anchor is installed is performed by a magnetostriction method. At this time, the anchor cap 10 and the seal piece 8 are removed, and the respective measuring methods are carried out.
Of course, if the strain gauge is operating soundly after the PC anchor is installed, it can be performed by both the magnetostrictive method and the strain gauge method. In this case, the measurement result of stress measurement by the magnetostrictive method is distorted. It is possible to verify by the measurement result by the gauge method.
[0041]
If the strain gauge is operating soundly, continuous monitoring is performed using the strain gauge method, and only when an abnormality is detected, the stress is measured using the magnetostriction method to check whether the strain gauge is abnormal. Alternatively, it can be determined whether the member to be measured 5 is abnormal. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
[0042]
In addition, the stress measurement by the magnetostriction method and the stress measurement by the strain gauge method are respectively performed on the three measurement surfaces, the average value thereof is obtained, and the stress measurement is performed, thereby improving the accuracy of the measurement result.
[0043]
FIG. 6 relates to the second embodiment, and shows a longitudinal cross-sectional view of the PC anchor and each part thereof. The second embodiment is different from the first embodiment in that the seal piece and the anchor cap are integrally formed. Accordingly, in the description of the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals in the drawings, the description thereof is omitted, and different parts are mainly described.
[0044]
As shown in FIG. 6, the anchor cap 20 is formed into a shape such that the seal piece 8 and the anchor cap 20 in the first embodiment are integrated, and a flange portion 20A is integrally formed at the opening edge thereof. In addition, a reduced diameter portion 20B having a smaller diameter than the other portions is formed at a substantially central portion in the length direction.
[0045]
When the anchor cap 20 is covered with the tip of the PC steel rod 1, the flange portion 20A at the opening edge of the anchor cap 20 comes into surface contact with the anchor plate 3, and the reduced diameter portion 20B is in contact with the cap nut. 7 is fitted almost exactly on the peripheral surface. Thereby, the anchor cap 20 covers and protects the front-end | tip part of the PC steel bar 1, the nut 4, the plain washer 6, and the member 5 to be measured.
[0046]
Thus, if the tip of the PC steel rod 1, the nut 4, the flat washer 6 and the member to be measured 5 are covered with one anchor cap 20, the number of parts can be reduced and the manufacturing cost can be reduced. In addition, the measurement can be performed only by removing one anchor cap 20 at the time of measurement.
[0047]
In each of the above embodiments, the member to be measured 5 has a hexagonal cross section, and the magnetostrictive measurement surface 5A and the strain gauge method measurement surface 5B are alternately arranged in the circumferential direction of the member 5 to be measured. However, the present invention is not limited to this, and may be a rectangle, an octagon, or the like. Further, the number of side surfaces is not limited to an even number, and may be an odd number. Furthermore, as long as the curvature is large and measurement is possible, the shape may be cylindrical, or as shown in FIG. 7, the strain gauge method measurement surface 5B is a curved surface and the magnetostriction method measurement surface 5A is a plane. It may be a thing.
In the above embodiment, the present invention is applied to a PC anchor. However, the present invention is not limited to this, and can also be applied to a ground anchor, an anchor bolt, and the like. Not only, but also a tension material such as a PC wire, a steel rod, or a cable (a tension material) such as a suspension bridge or a cable-stayed bridge may be used.
[0048]
【The invention's effect】
As described above, the tension member fixing portion structure of the present invention includes a member to be measured having an annular shape between the anchor plate and the fixing member, and the outer surface of the member to be measured is measured by a magnetostrictive method. Since the strain gauge is attached to the measurement surface by the strain gauge method, it is possible to measure with sufficient accuracy only by the stress measurement by the magnetostriction method, so the transition of stress over time can be easily measured. can do. If the strain gauge is operating soundly, continuous monitoring is performed using the strain gauge method, and only when an abnormality is detected, the stress is measured using the magnetostriction method, and whether there is an abnormality in the strain gauge. Alternatively, it can be determined whether the member to be measured is abnormal. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
[0049]
If the cross-sectional shape of the member to be measured is a polygon, a plurality of measurement surfaces can be formed, and it can be expected that the stress of the tendon is measured with higher accuracy.
[0050]
If the cross-sectional shape of the member to be measured is an even-numbered polygon, the number of magnetostrictive measurement surfaces and the number of strain gauge measurement surfaces can be the same and the number can be the same, and it is expected that the stress measurement of the tendon will be performed more accurately. it can.
[0051]
When the magnetostrictive method measurement surface and the strain gauge method measurement surface are alternately provided in the circumferential direction of the member to be measured, a measurement result with little deviation can be obtained, and it can be expected that the stress of the tendon is measured with higher accuracy.
[0052]
If a flat washer is interposed between the fixing member and the member to be measured, the stress distribution in the cross-sectional direction applied to the member to be measured can be made uniform, and the measurement accuracy can be increased.
[0053]
When the outside of the member to be measured is covered with the seal piece, the member to be measured can be protected, and the measurement of the member to be measured can be performed stably.
[0054]
If the fixing member and the tip of the tendon are covered with an anchor cap, the tip of the fixing member and the tendon can be protected, and the measured member can be stably measured.
[0055]
If the seal piece and the anchor cap are integrally formed, the number of parts can be reduced and the manufacturing cost can be reduced, and only one of them can be removed at the time of measurement, and the measurement can be performed easily. .
[0056]
When grease is filled in the seal piece and / or the anchor cap, the fixing member and the tip of the tension member and / or the member to be measured can be protected, and the member to be measured can be stably measured.
[0057]
In the stress measuring method of the tendon according to the present invention, the outer surface of the member to be measured is a magnetostrictive method measuring surface and a strain gauge method measuring surface, and a strain gauge is attached to the measuring surface by the strain gauge, and the magnetostrictive method measuring surface is attached. Applying a detection probe of the magnetostriction measuring instrument, applying a tension load when installing the tension material, collecting the strain gauge stress value by the strain gauge method and the output value of the magnetostriction measuring instrument, and increasing the stress sensitivity of the magnetostriction measuring instrument. Since the stress measurement after installation of the tendon material is performed by the magnetostriction method, it is possible to measure with sufficient accuracy only by the stress measurement by the magnetostriction method. Can do.
[0058]
In addition, when the strain gauge is operating soundly, continuous monitoring is performed by the strain gauge method, and only when an abnormality is detected, the site can be visited and stress measurement can be performed by the magnetostriction method. Whether the gauge is abnormal or the member to be measured is abnormal can be determined. That is, it is possible to go to the site only when an abnormality occurs, and the cost can be reduced accordingly.
[0059]
Furthermore, the stress sensitivity of the magnetostriction measuring device is obtained when a tension load (preload) is applied during the installation of the tendon material. For example, in the laboratory, the stress sensitivity using the same material as the tendon material is obtained in advance. Therefore, it is possible to simplify the measurement work. That is, the stress sensitivity can be collected by a tension load (preload) that is essential when the tendon is installed, and an extra step (collecting stress sensitivity in the laboratory) can be omitted.
[0060]
When the cross-sectional shape of the member to be measured is polygonal, and the stress measurement by the magnetostrictive method and the stress measurement by the strain gauge method are performed at a plurality of locations, respectively, a plurality of magnetostrictive method measurement surfaces and strain gauge method measurement surfaces are provided. The same number can be used, and it can be expected that the stress of the tendon is measured with higher accuracy.
[0061]
If the cross-sectional shape of the member to be measured is an even polygon, and the stress measurement by the magnetostrictive method and the stress measurement by the strain gauge method are performed at the same number of locations, the magnetostrictive measurement surface and the strain gauge measurement surface It is possible to make a plurality of and the same number, and it can be expected that the stress of the tendon is measured with higher accuracy.
[0062]
When the magnetostrictive method measurement surface and the strain gauge method measurement surface are alternately provided in the circumferential direction of the member to be measured, and the stress measurement by the magnetostriction method and the stress measurement by the strain gauge method are respectively performed, measurement results with little bias are obtained. Therefore, it can be expected that the stress of the tendon is measured with higher accuracy.
[0063]
By averaging the measured stress values by the magnetostriction method and the strain gauge method measured at multiple locations, it is possible to obtain a measurement result with less bias and to expect more accurate stress measurement of the tendon. .
[Brief description of the drawings]
FIG. 1 shows a first embodiment of the present invention together with FIGS. 2 to 5, and this figure is a longitudinal sectional view of a PC anchor and each part thereof.
FIG. 2 is an enlarged plan view showing a member to be measured.
FIG. 3 is an enlarged longitudinal sectional view showing a member to be measured.
FIG. 4 is an enlarged longitudinal sectional view showing a seal piece.
FIG. 5 is a graph showing a relationship (stress sensitivity) between a stress value and an output value of a magnetostriction measuring device.
FIG. 6, showing a second embodiment of the present invention, is an enlarged longitudinal sectional view showing a tip end portion and an anchor cap of a PC anchor.
FIG. 7 is a plan view showing deformation of a member to be measured.
[Explanation of symbols]
1 PC steel bar (tension material)
1A Bolt part 1B Buried part 2 Concrete 3 Anchor plate 4 Nut (fixing member)
5 Member to be Measured 5A Magnetostrictive Method Measuring Surface 5B Strain Gauge Measuring Surface 6 Plain Washer 7 Cap Nut 8 Seal Piece 9 Grease 10 Anchor Cap 10A Reduced Diameter Part 11 O Ring 20 Anchor Cap 20A Flange Part 20B Reduced Diameter Part

Claims (13)

A tension member (1), a fixing member (4) fixed to the tip of the tension member (1) and tightened to apply tension to the tension member (1), and a tension member than the fixing member (4) A fixing portion structure of a tension member (1) having an anchor plate (3) disposed at a position opposite to the tip of (1) and receiving a fixing force of a fixing member (4),
An annular member to be measured (5) is interposed between the anchor plate (3) and the fixing member (4),
The outer surface of the member to be measured (5) covered with the seal piece (8) is a measurement surface (5A) by the magnetostriction method and a measurement surface (5B) by the strain gauge method, and the measurement surface (5B) by the strain gauge method is used. A structure for fixing a tension material, which has a strain gauge attached thereto.   2. The tension member fixing portion structure according to claim 1, wherein the member to be measured (5) has a polygonal cross-sectional shape.   3. The tension member fixing portion structure according to claim 2, wherein the cross-sectional shape of the member to be measured (5) is an even-numbered polygon.   4. The tension material fixing according to claim 3, wherein a measurement surface (5A) by a magnetostriction method and a measurement surface (5B) by a strain gauge method are alternately provided in a circumferential direction of the member to be measured (5). Part structure.   The tension according to claim 1, 2, 3 or 4, wherein a plain washer (6) is interposed between the fixing member (4) and the member to be measured (5). Material fixing part structure. Covering the tip at the anchor cap (10) of the fixing member (4) and tension member (1), according to claim 1, characterized in that, according to claim 2, claim 3, claim 4 or claim 5 The structure of the fixing part of the tension material. The tension member fixing portion structure according to claim 6 , wherein the seal piece (8) and the anchor cap (10) are integrally formed. The tension member fixing portion structure according to claim 6 or 7 , wherein the seal piece (8) and / or the anchor cap (10) is filled with grease (9). Tension material (1), fixing member (4) fixed to the tip of the tension material (1) and tightened to apply tension to the tension material (1), and tension material than the fixing member (4) A tension member provided with a fixing portion structure of a tension member (1) having an anchor plate (3) disposed at a position on the opposite side of the tip of (1) and receiving the fixing force of the fixing member (4). A stress measuring method of
A member to be measured (5) having an annular shape is interposed between the anchor plate (3) and the fixing member (4), and the outer surface of the member to be measured (5) is connected to a measurement surface (5A) by a magnetostriction method. As a measurement surface (5B) by the strain gauge method,
While affixing the strain gauge to the measurement surface (5B) by the strain gauge, the detection probe of the magnetostriction measuring device is applied to the measurement surface (5A) by the magnetostriction method,
Applying a tension load at the time of installation of the tension material (1), collecting the strain gauge stress value by the strain gauge method and the output value of the magnetostriction measuring instrument, obtaining the stress sensitivity of the magnetostrictive measuring instrument,
A stress measurement method for a tension material, characterized in that stress measurement after installation of the tension material (1) is performed by a magnetostriction method. The tension according to claim 9 , characterized in that the cross-sectional shape of the member to be measured (5) is polygonal, and stress measurement by the magnetostrictive method and stress measurement by the strain gauge method are respectively performed at a plurality of locations. Material stress measurement method. A polygonal cross-sectional shape is an even number of the object body (5), the stress measurement by stress measurement and strain gage method according magnetostrictive method respectively to perform the same number a plurality of locations, it in claim 10, wherein The stress measuring method of the described tendon. A measurement surface (5A) by the magnetostriction method and a measurement surface (5B) by the strain gauge method are alternately provided in the circumferential direction of the member to be measured (5), and stress measurement by the magnetostriction method and stress measurement by the strain gauge method are performed, respectively. The stress measuring method for a tendon according to claim 11 , wherein the stress is measured. The stress material according to claim 9, claim 11, claim 11, or claim 12 , wherein stress values measured by a magnetostrictive method and stress values measured by a strain gauge method measured at a plurality of locations are averaged. Stress measurement method.

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